D.C. Mun. Regs. tit. 7, r. 7-1522
The Board shall certify the results of each election and publish the results in the District of Columbia Register and on the Board's website.
The election results shall be deemed final and not subject to further administrative review thirty (30) days after publication in the District of Columbia Register of the certified election results, or any amendment to the certified election results required after a petition for recount, which resulted in a change to an election winner.
Following certification of the results of the election, the Board shall retain and store in a secure and locked storage location, all election materials used during the election cycle where they shall remain for at least thirty (30) days after the certified election results have been published in the District of Columbia Register.
D.C. Mun. Regs. tit. 7, r. 7-1522